(There are cost benefit discussions on the linked pages…)
Residential natural gas –
1,000 tonnes a year of reductions = Converting 200 houses using gas to zero-emissions electricity.
PSE’s average household uses 64 therms/month, and combustion emissions are 11.7 lbs CO2e/therm. As I read the TCAT inventory, we’re including an estimate of upstream emissions from the production, transmission and distribution of gas in the baseline inventory, and estimating those at 25% of the combustion emissions. That works out to 14.6 lbs/CO2e per therm. So our average house using gas produces 11,232 lbs/CO2e each year, or 5 metric tons, and to get 1,000 tonnes a year of reductions, we would need to convert 200 houses.
All electric transportation –
1,000 tonnes a year of reductions = Converting 217 gasoline cars to plug-ins.
An average gas car, driving the average Thurston County annual miles, emits 4.6 tonnes CO2e/year, so to get 1,000 tonnes a year of reductions, we need to convert 217 gasoline cars to EVs. We only get these reductions for the life of the cars, though – maybe 12 years. (We might convert roughly 8% of IT’s 2018 fleet travel to electricity instead. In 2018 IT had 71 buses, 47 Dial a lift Vans, and 256 Van Pool vans; 8% would be roughly 5.7 buses, 4 Dial-A-Lift vans, and 20 Van Pool vans.)
Agricultural sequestration –
1,000 tonnes a year of reductions = Converting slightly over 1,000 acres of cropland from conventional to regenerative agriculture.
This is based on the most generous estimate I’ve got of potential reductions from regenerative agriculture. (There are 22,000 acres of cropland in the county; 14,000 acres of that is hay.)
Sequestration from new forests –
1,000 tonnes a year of reductions = Adding 400 additional acres of mature canopy in the county.
We currently have 235,851 acres of canopy cover in the county. (Filling all the 9,000 available spaces for street trees in Olympia would be the rough equivalent of thirty acres.)
Residential Solar Panels –
1kW of solar in our area produces an average of 1,059 KWh of power a year, and avoids 1,091 lbs of CO2e/year, given PSE’s current emissions. At that rate, we’d need 2,016 kW of solar, or 504 4kW rooftop arrays, to get 1,000 tonnes a year of reductions. (However, PSE will have to eliminate coal power from the grid by 2025, and at that point, a kW of solar will only avoid 633 lbs of CO2e/year. By 2030, our grid is supposed to be “carbon neutral”, and if it is, the panels will not be avoiding any emissions after that, though they may have other benefits.)