Can California really be carbon-free by 2045?

Solar panels on the roof of the Los Angeles Convention Center. Image: Getty.

California governor Jerry Brown recently signed a new law mandating that the electricity the state consumes not cause carbon emissions by 2045.

He also issued an executive order that goes even further: it commits California to “achieve carbon neutrality” across the board and not just for power generation by 2045. Together, these steps codify California’s ongoing transition away from relying on fossil fuels for energy. This effort has been ramping up since 2011, when Brown signed another law committing the state to deriving a third of its energy from renewable sources like wind and solar power by 2020 – not including big hydroelectric dams.

Based on more than 30 years of research related to solar energy, by my assessment, California can meet the law’s ambitious goal as long as it continues to implement programs that encourage the rapid expansion of renewable energy in the state.

A growth industry

The new law actually sets multiple targets rather than just one. It commits California to draw half its electricity from renewable sources by 2026, a share that would rise to 60 per cent by 2030.

To take the next step, rather than mandating that all power be renewably sourced, state lawmakers established a 100 per cent “zero-carbon” goal. They did not define this term, but it is understood as including wind and solar power, big hydropower plants and other sources of electricity that do not generate carbon dioxide.

Utility-scale solar and wind electricity increased from 3 per cent in 2010 to 18 per cent in 2017 in California, exceeding prior state targets, largely because solar prices have dropped sharply in recent years.

Being open to a wide range of technologies makes meeting the 2045 target easier and allowed State Senator Kevin de Leon, the original bill’s author, to amass broad support for the bill.

Where things stood in 2017

About 56 per cent of the power California generated in 2017 came from sources that don’t emit carbon. That puts it more than halfway toward this new goal by 2045.

However, the Diablo Canyon plant, California’s last nuclear power station, is slated for decommissioning by 2025, and no other reactors are in the works. This closure would eliminate the 8.7 per cent of the state’s carbon-free power that came from nuclear energy.

Nearly all of the remaining 44 per cent of the state’s electricity is currently generated by burning natural gas, and virtually none comes from coal. Going completely zero-carbon would require phasing out the state’s natural gas power plants.

On top of wind and solar energy, other generation options include geothermal, small nuclear reactors and carbon dioxide sequestration.

One quirk about this legislation is that it deals only with utility-scale power. It would not preclude private electricity-generation facilities such as the diesel generator a farmer might use to pump water. Nor would it count the power generated by a homeowner’s rooftop solar panels.

When the sun shines

One complication is that the state’s mix of energy sources can vary a great deal, even from one hour to the next.

Consider what happened on 8 April 2018, for example. It was a generally sunny and windy Sunday, with relatively low electricity demand. At night, about 40 per cent of electricity was generated from renewable sources. But around noon that day, more than 80 per cent came from renewable sources including large-scale hydropower.

If the electricity generated from these renewable sources is approximately doubled, as I estimate is necessary to meet the 2045 target, the power available in the middle of the day would greatly exceed the demand for electricity at that time.

This challenge shifts throughout the year.

On 24 and 25 July, Californians were asked to voluntarily use less electricity between 5 p.m. and 9 p.m. to avoid an outage because of hot weather. Prices spiked by more than a factor of 10, helping to keep demand within the supply.

On those days, renewably sourced electricity never met half of the demand for power.

Balancing act

Due to this degree of variability, relying heavily on renewable energy will require ample energy storage and big investments in grid-based technology.

Today, the expected demand for electricity is balanced by the Independent System Operator, an entity that controls the flow of electricity on the grid and selects the lowest-priced sources of electricity available.

Pumped hydro storage, electricity generated from water pumped to a reservoir, is the state’s most common form of storage today. While limited to locations with large dams, the amount of energy stored this way could be increased in California, as recently proposed for Hoover Dam.

Big lithium ion batteries are becoming more affordable and are now beginning to be deployed on the utility scale. As battery and solar prices drop, it may become attractive to disconnect from the grid and use electricity generated by a solar system and stored by a battery.

Lower battery costs are also spurring the sales of more electric vehicles. Ideally, these vehicles could be charged at times when electricity is plentiful and cheap. By 2045, I believe they could be helping make the grid more stable.

Other options are becoming available. One example is utility-scale compressed air storage, where energy is stored as pressurised air.

And there is growing interest in solar thermal plants, which generate electricity from sunlight’s heat and use high-temperature storage to continue generating electricity after the sun sets.

The University of California Merced and many other wholesale electricity customers are saving money by using thermal storage. They chill water when rates are low and use the chilled water for air conditioning when electricity prices are high.


Wiggle room

Because California’s new law does not require that every watt be generated within California’s borders, utilities could keep buying electricity from nearby states, as long as they verify its origins are in keeping with the new law’s requirements.

And because the law does not define “zero-carbon,” it provides flexibility in how the state can meet this new target.

For example, California would allow the continued operation of natural gas plants when their output is coupled with purchase of renewable energy certificates, credits issued for the generation of renewable electricity that may be sold, from a utility that generates solar or wind power.

These credits arise through several kinds of arrangements. Perhaps the most common is through rooftop solar systems. Small-scale solar energy supplied about 5 per cent of California’s electricity in 2017. It is likely to grow because of California’s mandate for solar panels on most new homes, starting in 2020.

In assessing whether the goal of going zero-carbon by 2045 is realistic or not, it is worth considering that solar energy has grown for years at a pace that far exceeded projections: thanks to technological progress, government policies like California’s new law, market forces and the public’s demand for renewable energy.

The Conversation

Sarah Kurtz, Professor of Materials Science and Engineering, University of California, Merced.

This article is republished from The Conversation under a Creative Commons license. Read the original article.

 
 
 
 

So why is Peterborough growing so quickly?

Peterborough Cathedral. Image: Jules & Jenny/Flickr/creative commons.

The latest instalment of our series, in which we use the Centre for Cities’ data tools to crunch some of the numbers on Britain’s cities.  

The 2001 census put the population of Peterborough at 156,000. Some time before next spring, it’s projected to pass 200,000. That, for those keeping score, is an increase of about 28 per cent. Whether this makes it the fastest growing city in Britain or merely the second or the fourth – the vagueness of Britain’s boundaries means that different reports reach different conclusions – doesn’t really matter. This is a staggering rate of growth.

Oh, and since austerity kicked in, the city council has had its grant from central government cut by 80 percent.

Expansion on this scale and at this rate is the sort of thing that’d have a lot of councils in our NIMBY-ish political culture breaking out in hives; that seems to go double for Tory-run ones in Leave-voting areas. This lot, though, seem to be thriving on it. “I think the opportunity in Peterborough is fantastic,” says Dave Anderson, the city’s interim planning director. “We’re looking at growing to 235,000 by the mid-2030s.”

More striking still is that the Conservative council leader John Holdich agrees. “I’m a believer in ‘WIMBY’: what in my back yard?” he says. He’s responsible, he says, not just to his electorate, but “to our future kids, and grandkids” too – plus, at that rate of growth, a lot of incomers, too.

All this raises two questions. Why is Peterborough growing so quickly? And what can it do to prepare itself?

If you’re a little uncertain exactly where Peterborough is, don’t worry, you’re in good company. Until 1889, the “Soke of Peterborough” was an unlikely east-ward extrusion from Northamptonshire, far to its south west. Then it was a county in its own right; then part of the now-defunct Huntingdonshire. Today it’s in Cambridgeshire, with which it shares a metro mayor, the Conservative James Palmer. When I ask Holdich, who’s giving me a whistlestop tour of the city’s cathedral quarter, to explain all this, he just shrugs. “They keep moving us about.”

Sitting on the edge of the Fens, Peterborough is, officially, a part of the East of England region; but it’s just up the road from East Midlands cities including Leicester and Nottingham. I’d mentally pigeonholed it as a London-commuter town, albeit a far flung one; but when I actually looked it up, I was surprised to discover it was closer to Birmingham (70 miles) than London (75), and halfway up to Hull (81).


The more flattering interpretation of all this is that it’s on a bit of a crossroads: between capital and north, East Anglia and the Midlands. On the road network, that’s literally true – it’s where the A1 meets the A47, the main east-west road at this latitude – and railway lines extend in all directions, too.

All of which makes Peterborough a pretty nifty place to be if you’re, say, a large logistics firm.

This has clearly contributed to the city’s growth. “It has access to lots of land and cheaper labour than anywhere else in the Greater South East,” says Paul Swinney, director of policy at the Centre for Cities. “Those attributes appeal to land hungry, low-skilled business as opposed to higher-skilled more knowledge-based ones.”

That alone would point to a similar economy to a lot of northern cities – but there’s another thing driving Peterborough’s development. Despite being 70 miles from the capital, the East Coast Main Line means it’s well under an hour away by train.

In 1967, what’s more, the ancient cathedral city was designated a new town, to house London’s overspill population. The development corporation which owned the land and built the new town upon it, evolved into a development agency; today the same role is played by bodies like Opportunity Peterborough and the Peterborough Investment Partnership.

The city also offers relatively cheap housing: you can get a four-bed family home for not much over £200,000. That’s fuelled growth further as London-based workers scratch around for the increasingly tiny pool of places that are both commutable and affordable.

The housing affordability ratio shows average house prices as a multiple of average incomes. Peterborough is notably more affordable than Cambridge, London and the national average. Image: Centre for Cities data tool.

It’s made it attractive to service businesses, too. “London has probably played quite a big role in the city’s development,” says Swinney. “If you don’t want to move too far out, it’s probably one of the cheapest places to move to.”

The result of all this is that it has an unusually mixed economy. There’s light industry and logistics, in the office and warehouse parks that line the dual-carriageways (“parkways”) of the city. But there are also financial services and digital media companies moving in, bringing better paying jobs. In a country where most city economies are built on either high value services or land-hungry warehousing businesses, Peterborough has somehow managed to create a mixed economy.

Peterborough’s industrial profile: more services and less manufacturing, and more private and fewer public sector jobs, than the national average. Image: Centre for Cities.

At the moment, if people think of Peterborough at all, they’re likely to imagine a large town, rather than the fair-size regional city it’s on course to become. Its glorious 12th century cathedral – the hallmark of an ancient city, and at 44m still by far the highest spot on the horizon for miles around – is stunning. But it’s barely known to outsiders, and at least twice on my tour, the council’s communications officer proudly announces that the Telegraph named her patch as one of the best towns to live in within an hour of London, before adding, “even though we’re a city”. 

So part of the council’s current mission is to ensure that Peterborough has all the amenities people would expect from a settlement on this scale. “What the city needs to do is to adopt the mind-set of a slightly larger city,” says Anderson. Slightly smaller Swansea is developing a new music arena, of the sort Peterborough doesn’t have and needs. He frets, too, about retail spend “leaking” to Cambridge or Leicester. “Retail is now seen as a leisure activity: in the core of the city it’s important that offer is there.”

To that end, the early 1980s Queensgate shopping centre is being redeveloped, with John Lewis giving up a chunk of space to provide a new city centre cinema. (At present, the area only has road-side suburban multiplexes.) There’s major office, retail and housing development underway at North Westgate, as well as work to improve the walking route between the station and the commercial centre, in a similar manner to Coventry.

Fletton Quays. Image: Peterborough Investment Partnership.

Then there’s the city’s underused riverside. The council recently moved to new digs, in Fletton Quays, on the far bank of the River Nene from the centre. Across the river from the Embankment, the city centre’s largest green space, it’s a pretty lovely spot, of the sort where one might expect riverside pubs or restaurants with outdoor seating – but at the moment the space is largely empty. The Fletton Quays development will change all that, bringing more retail space and yes, new homes, too.

Jobs in Peterborough are unusually distributed around town: in many cities, most jobs are in the central business district. Image: Centre for Cities.

The big thing everyone agrees is missing, though, is a university. It already has the University Centre Peterborough, where degrees are provided by Anglia Ruskin University. The plan is for the site – a joint venture between ARU and Peterborough Regional College – to go its own way as an independent institution, the University of Peterborough, in autumn 2022. That should help provide the skills that the city needs to grow. A growing student population should also bring life and cash to the city centre. 

How big could Peterborough get? Could its enviable combination of good location and cheap housing and grand ambitions combine to make it the modern equivalent of Manchester or Liverpool – one of the great cities of the 21st century?

Well, probably not: “I think the optimum size for a city is probably about 250,000,” says Holdich. But that’s still a whole quarter bigger than now, and the council leader even discusses the possibility of refitting his dual-carriageway-based-city with some kind of light rail network to service that growing population. Peterborough’s not done growing yet.

Jonn Elledge is the editor of CityMetric. He is on Twitter as @jonnelledge and on Facebook as JonnElledgeWrites.

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