Welcome to the Sustainable Aviation Project Blog site. My goal with these posts is to keep interested parties up to date on developments as the project progresses. I am new to blogging, so please bear with me as I post updates.
We have $1,071,000 in funding approved to purchase the four (4) Pipistrel Alpha Electro trainers and chargers to support their operation at the four airports in Fresno County. We are now working to get the grant agreement developed and signed by our partner cities of Reedley and Mendota. Our target date for the grant agreement approval is the April 12 meeting for the granting agency, Fresno County Transportation Authority. Following the agreement approval, we should be able to order the aircraft and chargers by mid-April. Pipistrel is saying it will take about 6 months from date of order to receive the aircraft and equipment. This will mean that the planes and equipment should arrive in mid-October 2017, if we can process the order as planned. This is not a bad time of year in the San Joaquin Valley since the weather is still rather dry and temperatures are cooling off from summer.
Working with Pipistrel, we have determined that we can deploy three (3) 20 kW chargers that need 208/240 volt, 3-phase electricity and one (1) 10 kW charger that needs 208/240 volt single phase electricity to build our network of chargers for the aircraft operations at the four airports. One 20 kW charger is planned to be located at Reedley Municipal (O32), Fresno Yosemite International (FAT), and Fresno Chandler Executive (FCH). Mendota Municipal (M90) will get the 10 kW charger. The chargers are not fully weatherproof, so they must be located inside hangars. This is a photo of a charger at the Pipistrel factory in Slovenia and you can see it is not in a weatherproof enclosure.
City of Mendota will get two new hangars as part of the project and our plan is to install the single charger in one of the hangars and provide a plug to the charger in each hangar. This will require some wiring between the hangars, but since only one aircraft is being charged at a time, should not create any issue with charger capacity. Here is a photo of the new hangar design.
This design matches the current hangar structure on the field as seen in this photo.
Cost of Operation on Electricity:
This is the # 1 question I get asked about the project and the quick answer is that we don’t know for sure since nobody in the U.S. has operated these aircraft yet. However, we have come up with some estimates and here is what we think it will cost.
As context for people outside of California, our electricity costs here are some of the highest in the U.S., so costs for “fuel” in other areas could be much lower. Of course, our 100LL costs are some of the highest in the country, so we think it will balance out. In fact, the flight school that will be using the Alpha Electros is currently paying about $6.50 per gallon for avgas in their Piper Tomahawk trainers.
We are estimating the electricity “fuel” cost per hour at about $5 based on replacing 14 kWh of electricity for a 1 hour flight lesson at an average cost of $.35 per kWh. The planes will have 21 kWh capacity battery packs which yields 90 minutes of total flight time per charge and 14 kWh represents about 66% of that capacity for a 1 hour training mission. The $.35 per kWh is based on a Pacific Gas and Electric Company A-6 rate schedule (see this link for details http://www.pge.com/tariffs/tm2/pdf/ELEC_SCHEDS_A-6.pdf )for commercial property customers. The A-6 rate offers time-of-use electric costs that range from a maximum of $.55 per kWh for peak demand summer use from Noon to 6 pm weekdays to off-peak costs of $.18 per kWh from 9:30 pm to 8:30 am on weekdays and all day on Saturday and Sunday. Partial peak costs are $.25 per kWh weekdays from 8:30 am to Noon and 6 pm to 9:30 pm. The calculation is as follows:
The aircraft will fly 4 hours per day and operate 6 days per week. Each aircraft will be fully charged overnight using off-peak electricity at $.18 per kWh for the first hour of flight @ $2.52. Hour 2 will be charged using partial peak electricity at $.25 per kWh @ $3.50. Hour 3 will be charged using peak electricity at $.55 per kWh @ $7.70. Hour 4 will be charged at peak electricity at $.55 per kWh @ $7.70. This results in a weekday average cost of electricity for 56 kWh per day of $5.35 per hour. Weekend flights on Saturday will be a flat $2.52 per hour using the off-peak electricity. Total weekly cost of electricity is estimated to be $117.18 for 24 hours of flight time which yields an average cost of $4.88 per hour. This estimate is for summer operations.
During the winter, there is no peak demand costs, only partial and off-peak. In this case the average should be about $.19 per kWh for the 56 kWh used each day or $2.66 per hour.
Of course, all this is an estimate at this point, but we will be equipping each charger with a data logger device and track the usage each day.
That is it for now. Thanks for your interest in the project. More posts as the project progresses.