‘Aiming for 90% or more renewable energy in 2030 in order to achieve climate change targets of 80-90% reduction of CO2 from the power sector leads to economic savings, not costs.’
WHO: Cory Budischak, Department of Electrical and Computer Engineering, University of Delaware, Newark, Department of Energy Management, Delaware Technical Community College, Newark, USA
DeAnna Sewell, Heather Thomson, Dana E. Veron, Center for Carbon-Free Power Integration, School of Marine Science and Policy, College of Earth Ocean and Environment, University of Delaware, Newark, USA
Leon Mach, Energy and Environmental Policy Program, College of Engineering, University of Delaware, Newark, USA
Willett Kempton, Department of Electrical and Computer Engineering, University of Delaware, Newark, Center for Carbon-Free Power Integration, School of Marine Science and Policy, College of Earth Ocean and Environment, University of Delaware, Newark USA, Center for Electric Technology, DTU Elektro, Danmarks Tekniske Universitet, Lungby, Denmark
WHAT: Working out how you could power a region with renewable electricity and the cost of doing it
WHEN: 11 October 2012
WHERE: Journal of Power Sources, 225, 2013
TITLE: Cost-minimized combinations of wind power, solar power and electrochemical storage, powering the grid up to 99.9% of the time
This research from the US is quite practical. The researchers looked at the electricity use from 1999 – 2002 in the ‘PJM Interconnection’ which is a power grid in the North Eastern USA that includes Delaware, New Jersey, Pennsylvania, Virginia, West Virginia, Ohio and parts of Indiana, Illinois and Michigan.
They wanted to know what a renewable power grid would look like, how much it would cost and how you could do it. Research excitement!
So what does a renewable power grid look like in this area? It involves a combination of renewables, which are onshore wind, offshore wind and solar in multiple locations which provides the greatest range of renewable power sources (if the wind is still in one state, it may be blowing in the next state).
The first hurdle this team had to jump was storage. The most popular storage model for renewables is wind-hydro hybrids (which I’ve written about previously here), however in this corner of the USA, there’s not much hydro power. So the paper looked at the options of electric vehicle grid storage, hydrogen storage and battery storage (lithium titanate batteries for those playing at home).
They used the data from 1999-2002 to model the hourly fluctuations of electricity demand, which averaged out at 31.5 Gigawatts (GW) of 72GW of generation. They then matched the load hour by hour with renewables and worked out which was cheapest.
They calculated the costs with a level playing field, which means no subsidies. No subsidies for renewables, but also a magical time when there’s not billions upon billions of dollars each year for fossil fuel subsides as well.
The results were that a renewable grid with 30% of coverage produced 50% of the power required for the sample years, while a renewable grid that provided 90% of the power coverage produced double the power required and a renewable grid that provided 99.9% of the power coverage produced three times the energy required. The researchers found that an overproduction of renewable electricity was preferable to trying to exactly match the power required and also reduced the need for storage.
A few of the benefits they found were that offshore wind and solar often generate when inland wind doesn’t, and that there was greater over-supply of power in the winter months which could allow for natural gas heating to be replaced by renewable electric heating.
What about the costs? The researchers looked at what the cost was for power in 2010 dollars and then adjusted for efficiencies to estimate the 2030 cost of power for the model and the infrastructure.
The 2010 cost of power was 17c per Kilowatt hour (kWh), while a renewable grid with 30% coverage would cost 10-11c per kWh, a 90% renewable grid would cost 6c per kWh and a 99.9% renewable grid is at parity with the fossil fuel grid at 17c per kWh.
The reason the 99.9% cost is higher than 90% is because filling the gap of that final 9.9% requires more infrastructure to further diversify the grid, but I think the most important thing they found in their research is this:
‘The second policy observation is that aiming for 90% or more renewable energy in 2030, in order to achieve climate change targets of 80%-90% reduction of CO2 from the power sector, leads to economic savings, not costs.’
Yes, even in coal country in the USA, switching to a hybrid renewable system (in a level playing field) is cheaper than the current cost of fossil fuel electricity. It also comes with the added benefits of no mercury poisoning from coal fired power plants too!
The paper concludes that while excess power generation in a renewable grid is a new idea, it shouldn’t be too problematic since it saves on storage needs and is the most cost-effective variation.
Their advice for plucky leaders who would like to make this grid a reality? The most cost-effective way to build this grid is to aim for 30% renewables now, and phase in the rest to 90% in 2030. Each step along the way to more renewable power will not only be a climate saving step, it will save money as well.
Thanks for your giving me attention to the important paper. The point of this paper is useful to the current situation of Japan where nuclear energy has been discredited.
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