Not long ago, utilities envisioned a new renewable electricity system that would involve time-of-use rates and load management via smart meters. The idea was that customers would do laundry and charge electric vehicles (EVs) at night when the demand for electricity and prices were both low.
Grid customers and utilities have a long way to go to understand how this new system would actually work. Having lived off-grid in Vermont for more than 30 years — using solar, batteries and a backup generator — I have a good understanding of how to adapt to this new renewable energy system. What I have learned may be helpful to others.
Winter, Cloudy Days and Back-up Generation
In New England, there are long stretches from mid-November to mid-January when the days are gray and very little solar generation is possible. After a couple of days, my batteries no longer get charging from the sun, which means I have to run a generator fueled by gasoline, propane or diesel. There are currently no options other than fossil fuels. If I get an EV, I will have to run the generator to charge the battery during much of the winter. For those who are hooked to the regional grid, charging an EV in winter effectively means relying on natural gas, nuclear, and Hydro-Quebec.
Nighttime and Load Reduction
Some people point out that when the sun isn’t shining in the daytime, the wind is blowing at night. That’s true more often in winter than in summer, but there are many nights in winter when wind turbines in New England are not providing much electricity. And because industrial wind turbines create complex acoustic problems, more wind at night means less sleep for neighbors.
My location is not good for wind generation, so it has never been a cost-effective option. Nighttime is when I turn off almost everything that uses electricity. Some people who live off-grid turn off their whole system.
Everyone in Vermont who is net-metering is tied to the regional grid. Instead of charging EVs and doing laundry at night as previously envisioned, the goal should be to reduce how much electricity is used. How many people turn their computers off at night? How much electricity are you using unnecessarily at night? When I visit people’s homes, I often notice that pretty much everyone leaves their printers on all the time. Even when turned off, many electric devices draw what’s known as ‘phantom power.’ Best to plug everything into a power strip and turn the whole strip off at night.
Solar Net-Metering and Nighttime
Even more important to understanding this new electricity system is the role of net-metering, heat pumps, electric hot water heaters and EVs. Some people who have heat pumps and net-metered solar seem to believe that their solar array is powering their electric heat pump. This impression is fueled by the credit system, whereby excess daytime and summer generation can be credited on-bill to be used at night and in winter. Customers who generate more electricity than they use in summer and more credits than they can use in winter can even give them away to friends.
In reality, there is no such thing as banking excess solar generation to be used at night or in winter. If there is a stretch of cloudy days, I have to run the generator to charge the batteries. The same thing applies to the regional grid: heat pumps used at night are fueled by whatever source of power is available at the time. At night, GMP customers rely primarily on Hydro-Quebec and nuclear. Nobody in Vermont is operating a heat pump or charging an EV at night with solar electricity.
Batteries and Limits
Batteries have their limits. My system still uses lead-acid batteries, which provide longer storage than lithium-ion batteries, but battery technology still has a long way to go. It can definitely benefit the grid system for everyone to install batteries, but currently, batteries cannot replace the need for backup generation.
Know your Watts
I know the wattage of all my appliances. Washing machine: 700 watts. Vacuum cleaner: 1100 watts (adjustable downward). Before you buy, pay attention not just to Energy Star ratings but to the actual wattage rating on the machine. Appliances that require heating and would run for a long time, like toaster ovens and heat pumps, are off-limits for my system. I dream of a 300-watt cooktop, but most appliances on the market are upwards of 1500 watts.
So far, replacing fossil-fueled electric generation with renewable wind and solar + storage is viewed as simply swapping out one generation source for another. Renewable energy systems require a better understanding of how those systems work, how to adapt and use less, and how to be aware of consumption and times of usage.