How Do We Get to 100% Renewable Energy? Could be Storage, Storage, Storage

June 15, 2017 | 11:24 am
Photo: Chris Hunkeler/CC BY-SA (Flickr)
Mike Jacobs
Senior Energy Analyst

As communities, companies, and even entire Midwestern utility companies move to supply 100% of electricity needs from renewable energy, the question presents itself: is this even possible? The answer, it turns out, is yes—and it’s made possible by the technical capabilities of advanced energy technologies (and especially storage).

This is UCS, so let’s talk about how to get the hard stuff done. To replace conventional generation with renewables, eventually all the services from fossil-fuel power plants have to be supplied by adding wind, solar, smart consumer appliances and electric vehicles, and storage.

As renewable energy is added by businesses and utilities, here are 5 great building blocks for a future that is 100% renewable energy.

Hot water heated with solar energy is energy storage. credit: DIY Home Sweet Home

1. Solar is capable of so much more than energy

The utility industry has begun to recognize that new technologies available can provide the reliability functions they need. The adoption of digital controls on solar and wind systems, particularly the inverters, make reliability functions available and useful already, without storage.

The fastest changing parts of the power grid and thus the tool box of solutions are coming from solar—which has present deployments averaging over 10,000 MW per year—and the sudden return of interest and capital to utility-scale energy storage.

The California grid operator has taken the challenge posed by UCS to demonstrate that the solar farms being built today are capable of providing a range of “essential services.” See this summary of a field test where a solar farm demonstrated faster and more accurate performance than other generator types. Wind turbines have also demonstrated these capabilities.

2. Storage is becoming part of the power plant

New energy storage deployments demonstrate just how quickly we can overcome the limit that the sunset creates for solar. The trajectory of energy storage substituting for conventional generation can be traced from actual practices. Beyond the early or largest examples of non-battery energy storage recently illustrated in the New York Times, going forward, there is widespread and dramatic potential for the use of battery storage by businesses and hybrid power plants.

Battery storage added at a power plant, both conventional and renewables, can take on duties that were met by old generators. First seen in remote locations, battery storage paired with generation began in isolated grids in places like Hawaii and Chile where ancillary services from very small generator fleets were unavailable or constraining the grid operations. This helped establish the technical and commercial foundation for expansion to larger grids in the United States.

Recent energy storage deployments now demonstrate a turning point. Present state-of-the-art technology adoption includes manufacturer General Electric (GE) adding energy storage to improve the performance of its line of peaking plants.

With short duration storage now understood as providing ancillary and essential services, GE is delivering hybrid plants with storage and a gas turbine integrated in a system with a single set of controls. The GE hybrid system uses the storage to provide the reliability capabilities of the gas generator with instantaneous response, regardless of whether the unit is started and burning fuel when response is needed.

Switching to electric can include energy storage. credit: NRECA

3. Solar plus storage is getting cheap

Well before planning for large-scale grids that run on 100% renewable energy, long-duration storage is already being paired with variable renewable generation (solar now, look soon for wind), making it able to satisfy market, reliability, and regulatory requirements.

Last month, Tucson Electric Power announced a contract with major power plant company NextEra that should extend production from a large solar array for 4 hours, and operate with the technical capabilities of a conventional plant. The amazing power purchase agreement price, under $0.045/kWh over 20 years, should put everyone on notice that solar plus storage is a very serious competitor based on innovations and cost-reductions.

4. Storage can pay for itself

Batteries used at the customer’s home or business to supplement the grid can lower the need for utility plants. For example, customers with a demand charge can use energy storage (combined with solar or not) to reduce that charge.

This business model addresses the utility premise that a consumer demand charge reflects the need for utility plants. The regulators should note this charge has not been aligned to the utility’s system peaks, and more accurate matching of demand charges and system peaks will create a better regulatory outcome (i.e. lower costs for the utility and consumers) than current practice. Consulting firm McKinsey & Company advises battery storage changes the industry, and in more than a few ways.

5. The future is now

With the introduction of inverters and better energy storage, decision-makers are, for the first time, facing the reality that renewables and storage may be able to replace what’s currently used.

At present, grid operators are showing they can maintain reliability when renewable energy has reached 40-60% of electricity demand in particular hours. Competitive prices are driving more wind and solar every day. An energy future of 100% renewables can be seen as coming soon. With multiple business models for storage replacing conventional utility plant, we can see where this is headed.