How energy storage and renewable resources make a perfect team
March 31, 2016
Energy storage isn't new, so why is it making news? Simply put - it has the ability to put renewables on the map, even more so than they already are. Before you understand what energy storage truly means for the future of both renewable energy and the grid, you have to understand how energy storage, renewable generation and the grid work together.
Fossil fuels are forms of energy storage
Consider your phone, your laptop or even yourself - everything runs off of stored energy, whether it comes from electricity or food. The electric grid - the modern engineering Mecca - is sustained by fossil fuels, which in turn sustain themselves, according to CALMAC CEO Mark MacCracken. The electric grid happens to be one of the oddities in life that doesn't require energy storage - currently.
"This unnatural design works only because of the storage inherent in fossil fuels, coupled with massive oversizing of equipment and complex controls to make the electric grid react instantaneously to any change in demand, any moment of the year," MacCracken wrote in an American Society of Heating, Refrigerating and Air Conditioning Engineers (ASHRAE) journal. "As we move toward a higher percentage of renewables (or nuclear) on the grid, enormous amounts of energy storage are necessary to make that energy dispatchable when we need it."
So, under the current grid system, during the daytime peak when the demand for energy rises peaking plants are brought online to create the supply of electricity. This is both unsustainable and wildly inefficient especially as dirty coal and older natural gas nuclear plant generators are being retired. There isn't enough energy storage available today in buildings or the grid to store energy. Throw in a heatwave during the day when the grid is operating at capacity and you'll have a real issue on your hands if peaking units are not available. But the world is changing. Energy storage is being added to the grid in the form of batteries and biomass. Pumped hydro has existed in limited locales but siting issues have stunted its growth potential.
Renewable energy is the future
Renewable energy is also being added to the grid but solar and wind are intermittent in nature. They are a form of pure energy, while fossil fuels have storage built in. This means that if we remove fossil fuels from the grid we are removing the energy storage aspect that makes our grid work.
"Energy storage can open the doors for renewable energy supplying the grid."
To account for energy storage inherent in fossil fuels and the increase in renewable energy generated, the grid needs energy storage to proliferate. The good news? #StorageIsHere and it's encouraging more investment in renewable energy because energy storage removes the intermittency obstacle.
Energy storage allows the grid to do what intelligent building and facility managers are already doing - store electricity at night to be used during the day. Consider a thermal energy storage system, which draws electricity at night when demand is low and, therefore, prices are cheap. In fact, MacCracken noted the only form of energy that hasn't seen an increase in price over the last 40 years is off-peak electricity. Instead of using power for HVAC during the day when every other building is doing the same, these facility managers shift the cooling load to the night to take advantage of the cheaper energy prices. In the case of buildings with solar panels, thermal energy storage systems kick on when the sun isn't shining to avoid connecting to the grid, similar to a back-up generator but used every day, not just during outages. Not only does this save money and provide much needed resiliency, but it supports a more stable grid as well.
What does this mean for the building design professionals and building owners? A couple of things:
- Zero energy and more environmentally sustainable buildings will be less dependent on the grid. Instead of the commercial building or school relying and putting pressure on the grid, it can operate off of its own stored renewable energy. Buildings and eventually communities could go off the grid and support themselves through environmentally friendly energy sources.
- Reliability will become synonymous with electricity demand. Currently, demand can outstrip supply and send the grid into a brownout or blackout costing the economy billions. If transmission and distribution networks go down, energy storage can quickly respond and keep operations going until the grid is back up.
- As more renewables are added to the grid, grid load factors worsen and the cost of peak demand charges rises. Peak demand chargers refers to the most energy consumed in 15 minutes increments during a billing cycle. Buildings who can reduce their peak demand by avoiding connecting to the grid during peak usage times will save dramatically on energy costs.
Energy storage is quietly earning its keep - nearly 3.9 GW of energy storage is installed across the world, according to the Department of Energy. Thermal energy storage leads the way in innovation, with 1.7 GW of capacity currently in operational use.
