Correct

节省 vs 节约

/ jiéshěng vs jiéyuē /
Strokes

Formula

1
增产节约 (increase production and practice economy)
2
勤俭节约 (be diligent and thrifty)

Definition

节省 and 节约 both are Verb, which means [economize; use sparingly; save], means “to use manpower; material resources sparingly”.

Example

节省 is applied to concrete things; 节约 is mostly applied to greater things.
1) In examples ① ② ③, since all are applied to concrete things, it is better to use 节省, but in order to emphasize the significance, 节约 can also be used instead in examples ② and ③.

2) The two words are verbs, but they are descriptive, so they can be modified by adverbs of degree as in example ②.
1
Zhè
háizi
孩子
jiéshěng
节省
xiàlai
下来
de
língyòngqián
零用钱
juān
gěi
le
zāi
灾区
  

The child donated his savings to the disaster area.

2
guòzi
过日子
fēicháng
非常
jiéshěng
节省
  
(
jiéyuē
节约
  
)
  

She lives a thrifty life.

3
Shǐyòng
使用
zhèzhǒng
这种
cāozuò
操作
fāng
方法
  
,
可以
jiéshěng
节省
  
(
jiéyuē
节约
  
)
shíjiān
时间
  

This operating method can save a lot of time.

节约 is used in some set phrases; 节约 can also function as an adverbial, as in example ⑤.
增产节约 (increase production and practice economy) 勤俭节约 (be diligent and thrifty)
4
Zhège
这个
gōngchǎng
工厂
zhèngzài
正在
gǎo
zēngchǎn
增产
jiéyuē
节约
  

The factory is implementing the practice of economically increasing production.

5
Jiéyuē
节约
bàn
企业
shì
men
他们
de
yuán
原则
  

One of their business principles is to be economical in business.

Related

节省节约